<form class="add-member">
  <div class="input-append">
    <input type="text" name="group_member" placeholder="Username" required/>
    <button class="btn" type="submit" data-loading-text="<i class='fa fa-spinner fa-plus'></i> Adding&hellip;"><i class="fa fa-plus"></i> Add</button>
  </div>
</form>
